Editing ALGOL (section)

{{Short description|Family of programming languages}}
{{About|the programming language family||Algol (disambiguation)}}
{{Use dmy dates|date=February 2020}}
{{EngvarB|date=June 2022}}
{{Infobox programming language
| name = ALGOL
| logo = 1965 ALGOL-20 A Language Manual, Fierst et al - cover.jpg
| logo caption = A 1965 manual for ALGOL-20
| paradigm = [[Procedural programming|Procedural]], [[Imperative programming|imperative]], [[Structured programming|structured]]
| family = ALGOL
| designers = [[Friedrich Ludwig Bauer|Bauer]], [[Hermann Bottenbruch|Bottenbruch]], [[Heinz Rutishauser|Rutishauser]], [[Klaus Samelson|Samelson]], [[John Warner Backus|Backus]], [[Charles Katz|Katz]], [[Alan Jay Perlis|Perlis]], [[Joseph Henry Wegstein|Wegstein]], [[Peter Naur|Naur]], [[Bernard Vauquois|Vauquois]], [[Adriaan van Wijngaarden|van Wijngaarden]], [[Michael Woodger|Woodger]], [[Julien Green (computer scientist)|Green]], [[John McCarthy (computer scientist)|McCarthy]]
| released = {{Start date and age|1958}}
| typing = [[Static type|Static]], [[Strong and weak typing|strong]]
| scope = [[Scope (computer science)|Lexical]]
| implementations =
| influenced = Most subsequent imperative languages (including so-called ''ALGOL-like'' languages)<br/>e.g. [[PL/I]], [[Simula]], [[Pascal (programming language)|Pascal]], [[C (programming language)|C]] and [[Scheme (programming language)|Scheme]]
}}

'''ALGOL''' ({{IPAc-en|ˈ|æ|l|g|ɒ|l|,_|-|g|ɔː|l}}; short for "'''Algorithmic Language'''")<ref>The name of this language family is sometimes given in mixed case ([http://www.masswerk.at/algol60/report.htm ''Algol 60''] {{webarchive|url=https://web.archive.org/web/20070625171638/http://www.masswerk.at/algol60/report.htm |date=25 June 2007}}), and sometimes in all uppercase ([https://www.cs.ru.nl/~hubbers/courses/sl1/rr.pdf ''ALGOL68''] {{webarchive|url=https://web.archive.org/web/20140913132128/http://www.cs.ru.nl/~hubbers/courses/sl1/rr.pdf |date=13 September 2014}}). For simplicity this article uses ''ALGOL''.</ref> is a family of [[imperative programming|imperative]] computer [[programming language]]s originally developed in 1958. ALGOL heavily influenced many other languages and was the standard method for [[algorithm]] description used by the [[Association for Computing Machinery]] (ACM) in textbooks and academic sources for more than thirty years.<ref>[http://calgo.acm.org/ ''Collected Algorithms of the ACM''] {{webarchive|url=http://archive.wikiwix.com/cache/20111017235805/http://calgo.acm.org/ |date=17 October 2011}} Compressed archives of the algorithms. [[Association for Computing Machinery|ACM]].</ref>

In the sense that the [[Syntax (programming languages)|syntax]] of most modern languages is "Algol-like",<ref>{{cite web |url=http://www.eecs.qmul.ac.uk/~ohearn/Algol/intro.html |archive-url=https://web.archive.org/web/20111114122103/http://www.eecs.qmul.ac.uk/~ohearn/Algol/intro.html |title=Algol-like languages, Introduction |last1=O'Hearn |first1=P. W. |last2=Tennent |first2=R. D. |date=September 1996 |archive-date=14 November 2011}}</ref> it was arguably more influential than three other high-level programming languages among which it was roughly contemporary: [[FORTRAN]], [[Lisp (programming language)|Lisp]], and [[COBOL]].<ref>[http://groups.engin.umd.umich.edu/CIS/course.des/cis400/algol/algol.html "The ALGOL Programming Language"] {{webarchive|url=https://web.archive.org/web/20161006113915/http://groups.engin.umd.umich.edu/CIS/course.des/cis400/algol/algol.html |date=6 October 2016}}, University of Michigan-Dearborn</ref> It was designed to avoid some of the perceived problems with FORTRAN and eventually gave rise to many other programming languages, including [[PL/I]], [[Simula]], [[BCPL]], [[B (programming language)|B]], [[Pascal (programming language)|Pascal]], [[Ada (programming language)|Ada]], and [[C (programming language)|C]].

ALGOL introduced [[Block (programming)|code blocks]] and the <code>begin</code>...<code>end</code> pairs for delimiting them. It was also the first language implementing [[nested function]] definitions with [[lexical scope]]. Moreover, it was the first programming language which gave detailed attention to formal language definition and through the ''[[Algol 60#History|Algol 60 Report]]'' introduced [[Backus–Naur form]], a principal [[formal grammar]] notation for language design.

There were three major specifications, named after the years they were first published:
* [[ALGOL 58]] – originally proposed to be called ''IAL'', for ''International Algebraic Language''.
* [[ALGOL 60]] – first implemented as ''X1 ALGOL 60'' in 1961. Revised 1963.<ref name=":0">{{cite journal |title=Report on the Algorithmic Language ALGOL 60 |location=Copenhagen, Denmark |date=May 1960 |doi=10.1145/367236.367262 |issn=0001-0782 |author-first1=John Warner |author-last1=Backus |author-link1=John Warner Backus |author-first2=Friedrich Ludwig |author-last2=Bauer |author-link2=Friedrich Ludwig Bauer |author-first3=Julien |author-last3=Green |author-link3=Julien Green (computer scientist) |author-first4=Charles |author-last4=Katz |author-link4=Charles Katz |author-first5=John |author-last5=McCarthy |author-link5=John McCarthy (computer scientist) |author-first6=Peter |author-last6=Naur |author-link6=Peter Naur |author-first7=Alan Jay |author-last7=Perlis |author-link7=Alan Jay Perlis |author-first8=Heinz |author-last8=Rutishauser |author-link8=Heinz Rutishauser |author-first9=Klaus |author-last9=Samelson |author-link9=Klaus Samelson |author-first10=Bernard |author-last10=Vauquois |author-link10=Bernard Vauquois |author-first11=Joseph Henry |author-last11=Wegstein |author-link11=Joseph Henry Wegstein |author-first12=Adriaan |author-last12=van Wijngaarden |author-link12=Adriaan van Wijngaarden |author-first13=Michael |author-last13=Woodger |author-link13=Michael Woodger |editor-first=Peter |editor-last=Naur |editor-link=Peter Naur |journal=[[Communications of the ACM]] |volume=3 |issue=5 |pages=299–314 |s2cid=278290 |doi-access=free}}</ref><ref>{{cite web|title=Revised Report on the Algorithmic Language Algol 60|year=1963|url=http://www.masswerk.at/algol60/report.htm|access-date=8 June 2007 |archive-url=https://web.archive.org/web/20070625171638/http://www.masswerk.at/algol60/report.htm |archive-date=25 June 2007 |url-status=live}}</ref><ref>{{cite web|title=An ALGOL 60 Translator for the X1|year=1961|url=https://www.cs.utexas.edu/users/EWD/MCReps/MR35.PDF |archive-url=https://ghostarchive.org/archive/20221009/https://www.cs.utexas.edu/users/EWD/MCReps/MR35.PDF |archive-date=2022-10-09 |url-status=live|access-date=7 January 2021}}</ref>
* [[ALGOL 68]] – introduced new elements including flexible arrays, slices, parallelism, operator identification. Revised 1973.<ref name=a68>{{cite web|title=Revised Report on the Algorithmic Language ALGOL 68|year=1973|url=https://www.cs.ru.nl/~hubbers/courses/sl1/rr.pdf|access-date=13 September 2014|url-status=live|archive-url=https://web.archive.org/web/20140913132128/http://www.cs.ru.nl/~hubbers/courses/sl1/rr.pdf|archive-date=13 September 2014}}</ref>

ALGOL 68 is substantially different from ALGOL 60 and was not well received,{{according to whom|date=May 2023}} so reference to "Algol" is generally understood to mean ALGOL 60 and its dialects.{{citation needed|date=May 2023}}